Twisted: Unauthenticated Remote Denial of Service in the Twisted IRC Server via an Unbounded Line Buffer

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-115776
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-23 21:17:23 UTC
Updated2026-10-23 21:17:23 UTC
DescriptionTwisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.words.protocols.irc.IRC.dataReceived retains all bytes received without a line feed in its per-connection buffer and applies no maximum line length. The twisted.words.service.IRCUser server subclass inherits this behavior, and buffering occurs before PASS, NICK, or USER authentication commands. An unauthenticated connection can continuously grow the buffer until the shared server process runs out of memory and drops all users. This issue is fixed in version 26.10.0rc1.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-400 | CWE-770 | CWE-400 CWE-400: Uncontrolled Resource Consumption | CWE-770 CWE-770: Allocation of Resources Without Limits or Throttling

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Twisted Twisted affected < 26.10.0rc1 Not specified

References

ReferenceSourceLinkTags
github.com/twisted/twisted/releases/tag/twisted-26.10.0rc1 [email protected] github.com
github.com/twisted/twisted/pull/12771 [email protected] github.com
github.com/twisted/twisted/security/advisories/GHSA-53xc-49m8-p798 [email protected] github.com
github.com/twisted/twisted/commit/ac90fb7b0ab73688a581fcd9a7c0577ec8ca3059 [email protected] github.com
github.com/twisted/twisted/commit/01f8cff7753c1edac132380b2ea939fa6bdbab30 [email protected] github.com
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